For the sake of brevity, the essential generic charac ters given it) his Synoptic Table, (at p. 33, 84. of vol. ii. of the Fundanzentum Historix Naturalis Muscorum Frondosorunz)only arc exhibited.
Such is the first modification of Hedwig's system. Its great merit consistsin its placing the peristome full in the view of the botanical world, and making it the chief basis of generic distinction. The publication of this system commenced a new era in systematic muscology,—an era since which more progress has been made in the study than in all former ages. The former systcms WCIT not indeed at once relinquished for it. For more than twelve years aftcr its first publication, we find some of the most judicious botanists complaining of it, and set ting it aside, as too artificial. But every day contributed to make the defects of the Linnxan arrangement more and more apparent, while every day contributed also to remove some of the prejudices which impeded the re ception of Hedwig's system. In point of fact, the dif ferent arrangements which have been formed, and more or less widely received in Europe during the last thirty years, arc, with extremely few exceptions, to be consi dered as modifications of Hedwig's system, or as formed according to his principles. Those arrangements which form exceptions, have been little noticed, and still less followed. That, for instance, of the late ingenious Baron Palissot de Beauvais, has been very seldom noticed, ex cept with the view of censure ; and, as far as we know, has had only one follower, in Mons. Desmazieres of Lille. If our limits had permitted, We would have given a sketch of it as a curiosity.
In a few topical norm, the arrangement of Linnxus is still retained ; but in these works the species, far too numerous for the system, are in such confusion, that we consider these works as nearly quite useless in regard to Muscology.
The system of Hedwig was afterwards very consi derably modified by himself. Hedwigia was given up for Anictangium ; and the distinction between Gymnos tomum and Anictangium was made to consist in Gym nostomum having thc male flowers in a terminal head ; Anictangiurn having them axillary. The name Leersia,
vhich other botanists had begun to give to different ge nera, was exchanged for Encalypta ; Koclreutera, for the same reason, became Funaria; and in the species Alus corum, a posthumous work, published in 1801, ten new genera were added. After Tetraphis was inserted, 1. An drzea, defined teeth four, connected at the summit, (it should have been " Capsule quadrivalve," as Ehrhart had discovered long before. See Hooker, in Linn. Trans. v. x. p. 382-387.) Between Andrxa and Splachnum is inserted, 2. Octo blephat um, easily distinguished from Splachnum by the want of an Apophysis. After Encalypta (Leersia) of which the definition is altered to male flosver axillary, female terminal on the same plant, three new genera, 3. Pterigynandrurn, 4. Cynontodium, and 5. Didymodon have place. Pterigynandrum, in addition to the charac ter of Encalypta, has also male and female flowers axil lary on different plants. Cynontodium has both male and female flower terminal, and Didymodon, both male and female flower axillary. These exhaust the new ge nera with a single fringe.
In the division with a double fringe, we find first of the new genera, 6. Bartramia (immediately following 13uxbauinia.) and characterised by the inner Fringe being membranous, furrowed, contracted into a cone, finely lacinated at the orifice : Flowers united. After Neckera (the arrangement of the genera being somewhat differ ent in this scheme from the original one,) 7. Ortliotri chum, 8. Timmia, 9. Pohlia.—Orthotrichurn is charac terised by the inner fringe being of ciliary teeth, uncon nected ; those of the outer approaching each other in pairs. The remaining new genera belong to the subdi vision in which the cilia forming the inner fringe arise from a membranous base. Timmia has the teeth uni form, the male flower axillary, the female terminal. Pohlia has the teeth uniform, the flower united and ter minal. After Bryum is introduced, 10. Arrhenopterum, and these two genera are distinguished by Bryum having the male flower terminal. in a round head, and Arrhenop terum, as the name imports, the male flower axillary.